Schaltungsanordnung zur Ansteuerung eines bürstenlosen Gleichstrommotors

摘要

A circuit arrangement is provided for driving a brushless DC motor (10), which has a radially magnetised rotor (20), with the aid of a microprocessor. This circuit arrangement has a first regulator (36) and a second regulator (38) to whose inputs the differences between in each case one required current value (idd, iqd) and one actual current value (idm, iqm) of the virtual currents flowing in the direction of the magnetisation and transversely with respect to the direction of magnetisation are connected, and which form associated regulator output signals (Ud, Uq). A rotation-angle sensor (44) supplies angle-position information on the angular position of the rotor (20) of the DC motor (10). First transformation means (46) are used to carry out an "inverse PARK transformation" in order to convert the regulator output signals (Ud, Uq) into three-phase voltage values (UR<*>, US<*>, UT<*>) (R, S, T are equivalent to R, Y, B in the British system) for producing a rotating field in the stator (12) of the DC motor (10), the angle-position information obtained from the rotation-angle sensor (44) being connected to the transformation means (46) in addition to the regulator output signals. A converter (48) converts the three-phase voltage values into three-phase currents which are connected to three windings (14, 16, 18) of the stator (12) of the DC motor (10). At least two currents (iSm, iRm) are measured in the windings (14, 16). Second transformation means (54) are used to carry out a "PARK transformation" in order to convert the said two currents in the windings (14, 16) into the said required current values (idm, iqm) for the virtual currents. In order to reduce the technical complexity in the case of such a circuit, the first and second transformation means (46, 54) have a function-term memory (64) in which two blocks of function terms for the transformations are stored, for each transformed variable, at addresses which are in each case formed by the angle-position information as the first address element and one of the variables to be transformed as the second address element. A first of the variables to be transformed can be connected via a multiplexer (116) to the function-term memory (64) on the one hand as the second address element for a function term of the first block and subsequently as the second address element for a function term of the second block. A register (132) is used for buffer storage of the function term allocated to the angle-position information and to the first variable to be transformed. In addition, an adder (134) is provided to which the buffer-stored function term from the register (132) can be connected as well as that function term which is allocated to the angle-position information and the second variable to be transformed. A further simplification is achieved by the transformations being carried out partially digitally and partially in an analog manner.